Immobilization of Acetobacter sp CGMCC 8142 for efficient biocatalysis of 1, 3-propanediol to 3-hydroxypropionic acid

3-hydroxypropionic acid (3-HP) is an important chemical platform organic in material industry, daily chemical industry and biomedicine field due to its numerous valuable derivatives. However, no mature methods have been established in the synthesis industry for direct large scale production. The bacterium Acetobacter sp. CGMCC 8142 with high efficiency of alcohols oxidation property was immobilized for biosynthesis of 3-HP from 1, 3-propanediol (1, 3-PDO). Parameter values in mass transfer modeling indicated that mass transfer of immobilized biocatalysts affected the oxidation reaction (the internal effectiveness factor eta (i) < 1) but was not the rate-limiting step if Thiele modulus 1 > phi > 0.3. The optimal immobilization conditions for 3-HP biocatalysis was sodium alginate 40 g/L, gel beads diameter 1 mm, cross-linkage time 2 h and 0.1mM FeCl2. Immobilized cells showed promising substrate tolerance, pH stability, thermal stability and storability. After 5 cycles of reaction, 3-HP molar yield of immobilized beads was retained to 80.26%, and 66.95 g/L 3-HP were produced from 70 g/L 1, 3-PDO. The biocatalysis process of immobilized cells introduced in this study may provide an economical and efficiency alternative route for practical production of 3-HP.